"Name me one brand of standard of the shelf routers that supports IPIP"
Cisco Juniper Mikrotik
By the way, http://etutorials.org/Networking/Integrated+cisco+and+unix+network+architectures/Chapter+11.+VPN+Technologies+Tunnel+Interfaces+and+Architectures/IP-IP+Tunnel/ has a tutorial/lab on setting up IPIP tunnels on both Cisco and Linux systems. - Brian